The present invention concerns a method for creating a releasable joint between two components, in which one of the components is elastically deformed by radial compressive forces in such a way that one effective circumferential contour corresponds to the corresponding effective circumferential contour of the other component with a predefined clearance, so that the two components can be inserted into one another; and in which, after the two components have been fitted together, a compressive joint is created by the fact that the deformed component is elastically deformed back by reducing or discontinuing the radial compressive force.
Methods of this kind for creating a frictionally engaged joint between two components are known from DE 195 21 755 C1 and from DE 196 24 048 A1. With these methods, a polygonal or oval component is elastically brought in identical fashion into a round shape by the application of radial compressive forces, so that a round shaft can be installed while the radial compressive forces are maintained. When the radial forces are then reduced or discontinued, the deformed component springs back into its original oval or polygonal shape, so that the shaft is immobilized therein by way of a press fit. This manner of joining two components has proven entirely successful in practice. It is nevertheless often considered disadvantageous that extremely large compressive forces are necessary if the component to be deformed possess large wall thicknesses, and the deformations which occur can then also not be managed precisely, i.e. are to some extent undefined.
It is therefore the object of the invention to describe a method and a joining system of the kind cited initially with which these disadvantages can be overcome, i.e. which allow the easy utilization of components to be deformed that have a large wall thickness.
According to the present invention, this object is achieved in that what is used as the elastically deformable component is a hollow body that has multiple cavities in its wall; and that the radial compressive forces are exerted on the inner or outer contour of the hollow body located opposite the effective circumferential contour in such a way that their working lines, considered in the circumferential direction, run approximately centeredly through the cavities. It has been found that the cavities exhibit the deformation behavior of thin-walled components, and can be deformed with comparable energy expenditure, if their cross section is weakened in accordance with the present invention by cavities, and the radial deformation forces act in the region of the cavities.
According to an embodiment of the invention, provision is made for the hollow body used to be one whose cavities are closed toward the effective circumferential contour, the effective circumferential contour having, in the undeformed state, circumferential segments lying inside and outside the effective circumferential contour of the other component. For example, if a shaft is to be clamped from outside, the hollow body used is one whose cavities are provided in the region of those circumferential segments which, in the unclamped state, lie outside the circumferential contour of the shaft that is to be clamped, and the radial compressive forces are exerted on the cavities from outside. The result is that the regions of the hollow body lying between the force application pointsxe2x80x94i.e. those circumferential segments that lie, in the unclamped state, inside the circumferential contour of the shaftxe2x80x94are pushed outward, so that the shaft can be inserted into the hollow body.
If the hollow body is to be used to clamp a hollow shaft on the outside, the hollow body used is one whose cavities are provided in the region of those circumferential segments that lie, in the unclamped state, inside the circumferential contour of the other component, and the radial compressive forces are applied onto the hollow body from the inner side. The result of this is that the circumferential segments placed between the force application points, are drawn inwardly so that the hollow body can be inserted into the hollow shaft.
A further embodiment provides for using, as the elastically deformable component, a hollow body that has multiple recesses extending in the circumferential direction which, viewed in the circumferential direction, arc open in their center region toward the effective circumferential contour that comes into contact with the other component; and that the radial compressive forces are exerted on the inner or outer contour of the hollow body that lies opposite the effective circumferential contour in such a way that their working lines lie inside the opening regions of the recesses toward the effective circumferential contour, so that the body segments formed between the, opening regions are moved by the deformation substantially radially into the region of the recesses in this case, if radial compressive forces are exerted on the hollow body in the regions where the recesses open toward the effective circumferential contour, the result is that the body segments lying therebetween, at which the effective circumferential contour is constituted, are pulled radially into the region of the recesses, thereby achieving the clearance necessary for fitting together the two components.
For example, if a shaft is to be clamped from outside, what is used is a hollow body in the form, for example, of an annular element in which the recesses open toward the inner circumference; and radial compressive forces are exerted on the hollow body from outside. The result of this is that the regions of the hollow body lying between the force application points are pushed outward, thus also causing the body segments to be moved outward substantially without deformation, so that the shaft can be inserted into the hollow body. The recessesxe2x80x94which for example can be introduced into the hollow body by way of an electrodischarge machining operationxe2x80x94must possess a width in the radial direction such that the body segments have sufficient room to deflect, and can be configured, for example, in the form of radial slits or slots.
Because the effective circumferential contour of the deformable component is substantially the same in the loaded and unloaded states, particular machining operations in the manufacture of said component are not necessary. For clamping a round shaft, for example, all that is necessary is to create on the hollow body a round inner contour whose radius for producing the press fit is somewhat smaller than that of the shaft, i.e. in the unclamped state the inner contour lies completely inside the circumferential contour of the shaft that is to be clamped.
If a [hollow shaft is to be clamped externally with the] hollow body is to be clamped inside a hollow shaft, the recesses open toward the outer circumference of the hollow body and the radial compressive forces are applied onto the hollow body from the inner side. The result of this is that the body segments that are formed between the opening regions are pulled inward into the region of the recesses, so that the hollow body can be inserted into the hollow shaft. In this case as well, the radial movement of the body segments takes place substantially without deformation of the external effective circumferential contour, which correspondingly has, in the unclamped state, a circular shape whose diameter is somewhat greater than the inside diameter of the hollow shaft.
The cavities should extend over a substantial circumferential region of the hollow body. It has proven to be advantageous if they extend altogether over at least 2000, in particular over approximately 2800 to 3000, so that they are separated from one another only by narrow web regions. According to a preferred embodiment, a total of three recesses are provided in the hollow body, each extending over a circumferential region of 80 to 1000; preferably they are arranged uniformly distributed over the circumference.
Regarding further advantageous embodiments of the invention, reference is made to the dependent claims and to the description below of an exemplary embodiment referring to the appended drawings, in which: